Errors during virus and spyware definition updates or product upgrades

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Microsoft Security Essentials uses Microsoft Updates (MU) service to deliver the virus and spyware definition updates and product upgrades. The definition updates and/or the product upgrade failures are generally caused by this service and results in a “0x8*******” error. If you encounter these errors, please write down the exact error code and follow these steps.

Step 1: Restart the Microsoft Update (MU) service

In Windows 7

In Windows 7, click Start, and in the Search programs and files box, type services.msc, and then press Enter.

Right-click Windows Update, and then click Start. If Start is unavailable, click Restart.

In Windows Vista

In Windows Vista, click Start, and in the Start Search box, type services.msc, and then press Enter.

Right-click Windows Update, and then click Start. If Start is unavailable, click Restart.